The prior art shows various types of exercising devices that use cables, pulleys, elastic mechanisms, free weights and other loading devices. The devices may be used for bench presses, lat pulls, butterfly reps, arm and leg curls, squats, leg extensions as well as other exercises.
U.S. Pat. No. Re. 4,072,309 discloses a multi-purpose exercise device. The device provides for a variety of exercises using spring means such as shock cords to provide resistance. As the user moves a lever arm, the spring means resists the movement. However, this device has the drawback of an uneven force applied throughout the stroke. The uneven force results from the mechanics of a spring which applies little resistive force when stretched a short way, but applies an extremely high resistive force when stretched close to its maximum. Furthermore, these types of resistance devices can also be unsafe in that if the user loss his/her grip, the lever arm snaps quickly back into place, possibly injuring the user. Another disadvantage of this exercise unit is the angular displacement that the bench press/squat bar travels during the stroke. The pivot point of the bar is on the vertical member. As the bar is moved upward, it reduces the resultant angle between the bar and the vertical member, until at its maximum the bar touches the vertical member. This is not the desirable travel path a bar moves in a bench press or squat exercise.
Other exercise devices utilize free weights which are lifted with cables. Examples of this technology include U.S. Pat No. 4,678,185. However, these devices often result in injuries on the eccentric or down stroke of the lever arm. This is due to the fact that most weight lifting injuries occur after the user has forced the resistance mechanism to a maximum. The user is lowering the resistive force by returning the lever or pivot arm to its resting position and injuries tend to occur during this motion. Thus, it is preferred not to have any resistance on this eccentric portion of the exercise repetition.
Other resistance devices include isotonic devices which utilize a cam in conjunction with a stack of weights. The cam is shaped such that a chain around the cam gives the user a mechanical advantage during the portion of the stroke which the "typical" user is weakest. However, all users are not built the same, and the cam cannot possibly be designed for everyone. Thus, it would be desirable to have a resistance device which provides a resistance which reacts to the user, not built for a "typical" user.
None of these prior art devices show an apparatus which can provide a whole host of weight lifting exercises, yet provide the resistance in a safe, uniform manner. Furthermore, there is no disclosure of a resistance mechanism which responds to the user.
MGI Strength Fitness, Inc. makes and sells an isokinetic exerciser called the MINI-GYM, which has pull ropes that load in proportion to the amount of force being applied. The device can be either wall or floor mounted, or mounted on fixed frames for providing the resistance force for exercise. The devices are gymnasium type devices, and have the appearance of conventional exercisers. Flexible lines or ropes are used in various frame assemblies for these isokinetic exercisers. However, the MINI-GYM does not provide for a variety of upper and lower body exercises as necessary for a complete home unit.
The present invention provides the ability to do pullovers, pull downs, chest crosses, butterflies (with the arms either up or down), chest presses, bicep curls, leg curls, leg extensions, squats, etc. Thus, the present invention permits a wide range of exercises for complete conditioning in a safe and user friendly exercise apparatus.